Pusher box for nondestructive pipe refurbishment in confined spaces

ABSTRACT

Methods are disclosed for refurbishing an existing host pipe. According to presently preferred embodiments, a first phase is to make a longitudinal cut in the host pipe. A second phase is an expansion phase, wherein the host pipe is expanded, preferably nondestructively, via separation of the longitudinal cut. A third phase is to insert liner pipe sections into the expanded host pipe. In confined space environments, sections of liner pipe are concatenated end-to-end as they are inserted into the host pipe. In some embodiments, the expansion phase and the liner pipe section insertion phase may be combined. A fourth phase is to grout the annular space formed between the host pipe and the concatenated liner pipe sections.

PRIORITY CLAIM AND RELATED APPLICATIONS

This application claims priority to, and the benefit of,commonly-invented and commonly-assigned U.S. Provisional PatentApplication Ser. No. 62/471,389 filed Mar. 15, 2017. The entiredisclosure of 62/471,389 is incorporated herein by reference as is fullyset forth herein. This application is further related tocommonly-invented and commonly-assigned U.S. patent application Ser. No.14/732,565 filed Jun. 5, 2015 (hereafter, the “Prior Application”), nowU.S. Pat. No. 9,175,798 issued Nov. 3, 2015. The entire disclosure ofthe Prior Application is also incorporated herein by reference as iffully set forth herein.

FIELD OF THE DISCLOSURE

This disclosure is directed generally to a method for refurbishingburied expandable pipes without open cut replacement (i.e., withoutdigging the pipe out of the ground), where such pipes are located inconfined spaces, such as under roads in mountain passes with steepinclines on one side and open waterways nearby on the other side.

BACKGROUND

The term “expandable” is used as a defined term of art throughout thisdisclosure. By “expandable”, this disclosure refers to culverts andpipes that, when cut longitudinally in situ underground, may then beradially expanded, preferably nondestructively, by separation andwidening of the longitudinal cut, so that the expanded pipe (or expanded“host” pipe as sometimes referred to herein) may then receive a newinner liner pipe whose internal diameter is at least the same as, if notlarger than, the internal diameter of the original unrefurbished hostpipe. It is expected that many culverts or pipes falling within thisdefinition will be metal, and will be corrugated or “accordion” inprofile. However, the term is not limited to corrugated or accordionprofiles on metal pipes or culverts.

The Prior Application, incorporated herein by reference, discloses atrenchless technology, now patented, for nondestructively refurbishingunderground pipes. Generally speaking, the Prior Application describesembodiments in which a longitudinal cut is initially made in the hostpipe. In some embodiments disclosed in the Prior Application, the hostpipe is then radially expanded, preferably nondestructively, byseparation and widening of the longitudinal cut. A new liner pipe isthen inserted into the expanded host pipe. Preferably, the internaldiameter of the liner pipe is at least the same as, if not larger than,the internal diameter of the original unrefurbished host pipe. Grout maythen be injected into the annular space between the liner pipe and thehost pipe.

The Prior Application further describes some of the problems that itsdisclosed technology solves, and some of the technical advantagesenabled in solving such problems. While embodiments of the PriorApplication have been shown to be highly serviceable, and indeed highlyadvantageous, improvements have been identified in deployments where thehost pipe is located, for example, under roads in mountain passes withsteep inclines on one side and open waterways nearby on the other side.Such locations may often present additional access challenges indeploying the embodiments of the Prior Application. As is shown on FIG.1, host pipe H is buried beneath road R with steep incline SI on oneside and waterway W on the other side. In the exemplary environmentillustrated on FIG. 1, access to host pipe H on the waterway W side isfrom above only. Access to host pipe H on the other side is very limitedby steep incline SI. It will be appreciated that, for example, thelocation of host pipe H presents challenges to installing a new linerpipe inside host pipe H if the liner pipe is approximately the samelength as host pipe H. There is not enough room on the steep incline SIside to insert a full-length liner into the host pipe H from the inclineside, and waterway W prevents practical insertion of a full-length linerinto host pipe H from the water side.

Conventional prior art solutions to the above-described accesschallenges present additional problems. For example, a “cured in place”or “CIPP” method is known, in which a collapsible liner, or “sock” isunrolled into host pipe H and then expanded with steam and cured ontothe inside of host pipe H. Such CIPP solutions lack the structuralintegrity of a rigid liner pipe solution, and their robustness againstcracking and leaking in service is not as good as a rigid liner pipesolution.

SUMMARY OF DISCLOSED TECHNOLOGY AND TECHNICAL ADVANTAGES

This disclosure describes enhanced embodiments of the trenchlessunderground pipe refurbishment technology described in the PriorApplication. Embodiments of methods and apparatus described in thisdisclosure solve the problem of inserting a liner pipe into the hostpipe in deployments where physical space limitations make insertion of afull-length liner pipe impractical, if not impossible. According to theembodiments described in this disclosure, a confined space insertiontool (hereafter, a “pusher box”) enables the new inner liner pipe to beinserted into the host pipe in concatenated sections.

Functionally, the pusher box manipulates rods of pre-determined lengthinto and out of the host pipe once the pusher box has been positioned,leveled and stabilized at one end of the host pipe. Functions performedby the pusher box on the rods include inserting and retracting the rodsfrom the host pipe, rotating a rod string, and raising/lowering a rodstring with respect to the host pipe. With particular reference toinserting and retracting, the pusher box inserts rods in a concatenatedstring. Once the pusher box has inserted one rod into the pipe, the nextrod is concatenated to the trailing end of the previously-inserted rodbefore being pushed in, and so on. Retraction of the concatenated rodstring is the reverse operation. The pusher box pulls the rod string outso that the rods can be removed from the string one at a time. A rod isdisconnected from the retracted string as it emerges, allowing the nextrod in the string to be retracted.

The rods may preferably be used first in the host pipe cutting phase, inwhich a longitudinal cut is made in the host pipe to facilitatenondestructive expansion of the host pipe via separation of the cut.Some embodiments may use a self-propelled cutting tool such as describedin the Prior Application. Other embodiments may use a cutting tool thatis pushed into and retracted from the host pipe using rods and thepusher box as described below. In some embodiments, the cutting tool maybe “pushed while cutting” by inserting rods into a concatenated rodstring. In other embodiments (such as illustrated in this disclosure),the cutting tool may be “pulled while cutting” by retracting andremoving rods from the string once the cutting tool has been positionedat the far end of the host pipe by rod insertion. However, thisdisclosure is not limited to any particular design of cutting tool ordirection in which the cut is made using the rods in a rod string.

After the host pipe is cut, the rods may then preferably be used again,this time in conjunction with a pipe expansion tool in the host pipeexpansion phase. Preferred embodiments include a host pipe expansionphase, although the scope of the disclosed technology is not limited inthis regard. Preferred embodiments may use a pipe expansion tool such asis described in the Prior Application, or a lighter, smaller expansiontool as described in this disclosure. However, this disclosure is notlimited to any particular design of expansion tool. As will be describedin greater detail below, the pusher box may insert and retract a rodstring connected to the pipe expansion tool, which allows the operatorsto stop the expansion tool at desired stations along the length of thehost pipe interior in order to expand the host pipe at those stations.Additionally, the pusher box may rotate the rod string while the pipeexpansion tool is attached at a remote end. As a result, the pipeexpansion tool may also be rotated in a controlled way at each host pipeexpansion station, allowing for uniform radial expansion of the hostpipe at each station. Also, as with the disclosure regarding the cuttingtool immediately above, embodiments may use a “push and expand”technique on the pipe expansion tool (in which rods are inserted intothe concatenated rod string), while alternative embodiments may use a“pull and expand” technique (in which the rods are retracted and removedfrom the rod string once the pipe expansion tool has been positioned atthe far end of the host pipe via rod insertion). This disclosure is notlimited to any particular design of pipe expansion tool or direction inwhich host pipe is expanded using the rods in a rod string.

Note also that not all embodiments of an expansion phase require acutting phase. The scope of this disclosure includes some embodiments(not described herein in detail) in which expansion is sufficient to“smooth out” the wavy profile of a corrugated host pipe. Embodiments forexpanding a host pipe in this fashion are described in the PriorApplication, incorporated by reference herein. Once expansion of a hostpipe is complete in these “non-cut” embodiments, a liner pipe may beinserted into the host pipe in sections, consistent with the liner pipeinsertion phase described below in this disclosure.

Once the expansion phase is complete, the pusher box, in conjunctionwith the rods, then enables the liner pipe to be inserted into theexpanded host pipe in sections. Preferably, each liner pipe section isapproximately the same length as one of the rods. Away from the pusherbox, a rod is inserted into a liner pipe section, and is centered andfrictionally stabilized within the liner pipe section with wireframecentering balls that are attached to the rod along the rod's length. Thewireframe centering balls are sized and shaped to frictionally engagethe internal surface of the liner pipe so that the liner pipe sectionmay be inserted into the host pipe along with the rod. Advantageously,the liner pipe sections arrive at the pusher box in “cartridge” form,with a length of liner pipe already made up with the rods and wireframecentering balls pre-deployed inside. The cartridges may be of any lengthsuitable for the application, but are preferably selected from within arange from about 3 feet to about 7 feet in length.

Currently preferred embodiments of the liner pipe itself are a rigidliner pipe. More preferably, the liner pipe comprises galvanizedcorrugated metal pipe (“CMP”), although the scope of this disclosure isnot limited in this regard. Examples of other suitable rigid liner pipeconstructions include, without limitation, galvanized metal, aluminizedsteel, or asphalt coated steel pipe (corrugated or plain), or plastic,ceramic or a fiber reinforced resin compound pipe (corrugated or plain).

The pusher box inserts the liner pipe sections one by one into the hostpipe. As noted, the liner pipe sections are inserted by the rods. Aswith the host pipe expansion phase, the pusher box inserts rods (thistime with liner pipe sections attached) in a concatenated string. Oncethe pusher box has completed insertion of one rod into the pipe, thenext rod is concatenated to the trailing end of the previously-insertedrod before being pushed in. Each successive liner pipe section is alsoconcatenated to the trailing end of the previously-inserted liner pipesection before insertion by its corresponding rod.

The leading ends of the first rod and the first liner pipe section inthe string are preferably attached to a conically-shaped steel head,such that the steel head leads the entire string of rods into the hostpipe with concatenated liner pipe sections attached to the steel head.The steel head, with its dead weight and conical shape, assists thepusher box with smooth insertion of the entire concatenated string ofrods/liner pipe sections into the host pipe. In particular, the steelhead protects the leading edge of the first liner pipe section fromsnagging against corrugations and minor peripheral obstructions in theinterior of the host pipe. Embodiments herein of the steel head alsoadvantageously provide a vibrator that vibrates the steel head and thefirst rods/liner pipe sections in the string against the host pipeinterior as they are inserted into the host pipe. Alternatively, steelhead embodiments may provide an impact hammer on board to generate ajolting force. This vibration or jolting further assists the pusher boxwith smooth insertion of the entire concatenated string of rods/linerpipe sections into the host pipe. It will thus be appreciated that inpreferred embodiments deploying an attached steel head, the pusher boxis effectively pushing the steel head into the host pipe via the rods,and the liner pipe sections are being “dragged along for the ride”. Thatis, compressive force from the pusher box pushes the steel head furtherinto the host pipe via thrust through successive concatenated rods. Asthe steel head moves further into the pipe, the steel head drags theattached concatenated liner pipe sections behind it, even though theliner pipe sections are also disposed about the rods via frictionconnection through the wireframe centering balls. The concatenated linerpipe sections are thus subjected to a tensile force as they are draggedinto the host pipe, rather than to a compressive force from a “push”into the host pipe via the rods. In this way, the liner pipe sectionsare in lower jeopardy of buckling or collapsing compressively inresponse to the “push” force on the rods from the pusher box.

Once all of the liner pipe sections have been inserted into the hostpipe by the pusher box, and the steel head has emerged from the hostpipe at the far end, the steel head may be disconnected from the rodstring and the concatenated liner pipe sections, and then removed fromthe host pipe at the far end. The pusher box then retracts the rodstring, with the wireframe centering balls attached. The pusher boxpulls the rod string out so that the rods can be removed from the stringone at a time. A rod is disconnected from the retracted string as itemerges, allowing the next rod in the string to be retracted, and so on.In some embodiments, a combination of the dead weight of the entireliner pipe as now deployed in the host pipe, plus the frictionalresistance of the entire length of liner pipe against the host pipeinterior, is sufficient to hold the liner pipe in place while the rodstring is retracted from the liner pipe with wireframe centering ballsattached. In other embodiments, it may be preferable to initiallydisconnect only the rod string from the steel head, and leave the linerpipe temporarily connected to the steel head. In such embodiments, thedead weight and frictional resistance of the liner pipe as attached tothe steel head at the far end of the host pipe will enable the rodstring, with wireframe centering balls attached, to be retracted fromthe liner pipe without dislodging the liner pipe from within the hostpipe. Once the rods and wireframe centering balls are completelyretracted, the liner pipe may then be disconnected from the steel headat the far end of the host pipe. The steel head may be taken away,leaving the liner pipe in place in the host pipe.

Once the rod string is removed entirely from the host pipe, the annularspace between the host pipe and liner pipe may be injected with grout.Alternatively, grouting may be done before the rod string is removed toprovide yet further immobilization of the liner pipe during retractionof the rods and wireframe centering balls.

It should be noted that use of the wireframe centering balls in thisdisclosure is not limited to the above-described process of inserting aliner pipe in the host pipe. Although not specifically illustrated anddescribed below, the scope of this disclosure includes optionallyincluding the wireframe balls as centering devices on the rod stringduring host pipe cutting and expansion phases. Throughout the disclosedpipe refurbishment process, the centering function of the wireframeballs provides several advantages, including:

(a) Stabilizing the rods inside the liner pipe during insertion. As willbe described below, in preferred embodiments the compression “push”delivered by the pusher box to insert the liner pipe into the host pipemay be up to 85,000 lbs. The wireframe centering balls stabilize the rodstring to minimize lateral deflection of the rods under such a pushload.

(b) Centralizing the compression force during liner pipe insertion. Asnoted above, the compression force is preferably focused through to thesteel head at the leading end of the liner pipe as it is inserted intothe host pipe. The steel head then pulls the liner pipe into the hostpipe.

(c) When used in the cutting phase, centralizing the path of the cuttingtool during the host pipe cutting phase, thereby encouraging a truelongitudinal cut.

(d) When used in the expansion phase, centralizing the path of the pipeexpansion tool during the host pipe expansion phase, thereby encouragingcontrolled rotation and uniform expansion at each station.

According to a first aspect, therefore, embodiments of the disclosedtechnology provide a method for refurbishing an existing pipe, themethod comprising the steps of: (a) providing an existing host pipe; (b)inserting a concatenated string of liner pipe sections inside the hostpipe, step (b) further including: (b1) providing a plurality ofcartridges, each cartridge including (1) a liner pipe section, (2) atleast one rod and (3) at least one centering ball, wherein each rod andcentering ball is received inside the liner pipe section such that eachrod is stabilized within the liner pipe section via frictional contactbetween each centering ball and the liner pipe section; (b2) inserting afirst cartridge into the host pipe; (b3) concatenating the at least onerod in the first cartridge to the at least one rod in the secondcartridge; (b4) concatenating the liner pipe section on the firstcartridge to the liner pipe section on the second cartridge; and (b5)inserting the second cartridge into the host pipe; and (c) withdrawingthe rods and centering balls from within the concatenated string ofliner pipe sections.

In other embodiments, concatenating the liner pipe section on the firstcartridge to the liner pipe section on the second cartridge isaccomplished by a connection technique selected from the groupconsisting of: (a) clamping; (b) bolting; (c) riveting; (d) gluing withadhesive; and (e) welding.

In other embodiments, concatenating the liner pipe section on the firstcartridge to the liner pipe section on the second cartridge isaccomplished by making a threaded connection therebetween.

In other embodiments, the method may comprise, prior to step (b), thesteps of: (aa) providing an expander, the expander having a longitudinalexpander axis, the expander adapted to generate outward radial forceperpendicular to the longitudinal expander axis when the expander isactuated to expand; (ab) moving the expander along a path inside thehost pipe, the path having stations at which the expander stops; (ac)expanding the host pipe during step (ab), step (ac) further including,at each station: (ac1) stopping the expander; (ac2) responsive tooutward radial force from the expander, increasing an interior diameterof the host pipe; and (ac3) moving the expander to the next station. Inother embodiments, the method may further comprise rotating the expanderabout the longitudinal expander axis and repeating step (ac2). In otherembodiments, step (ab) further comprises concatenating a plurality ofcapsules into a string thereof, wherein the string of capsules isinserted into the host pipe to follow the expander as it moves.

In other embodiments, an annular space forms between the host pipe andthe concatenated string of liner pipe sections, and the method furthercomprises: (d) at least partially filling the annular space with grout.In other embodiments, the method may further comprise the steps ofstabilizing the concatenated string of liner sections with stabilizationmeasures before step (d) and removing the stabilization measures afterstep (d).

In other embodiments, the method may comprise, prior to step (b), thestep of making a longitudinal cut in the host pipe. The method mayfurther comprise inserting a plurality of capsules into the host pipe asthe longitudinal cut is made, wherein the capsules are in a concatenatedstring thereof.

In other embodiments, the first cartridge has a leading end and atrailing end as inserted into the host pipe, and a steel head isconnected to the leading end of the first cartridge such that the atleast one rod in the first cartridge is connected to the steel head. Thesteel head may be conically shaped. The first cartridge may also beconnected to the steel head. In other embodiments, the steel headincludes a vibrator, and step (b) further includes vibrating the steelhead during insertion. In other embodiments, the steel head includes animpact hammer, and step (b) further includes jolting the steel headduring insertion.

According to a second aspect, embodiments of the disclosed technologyprovide a method for refurbishing an existing pipe, the methodcomprising the steps of: (a) providing an existing host pipe; (b)providing an expander, the expander having a longitudinal expander axis,the expander adapted to generate outward radial force perpendicular tothe longitudinal expander axis when the expander is actuated to expand;(c) moving the expander along a path inside the host pipe, the pathhaving stations at which the expander stops; (d) expanding the host pipeduring step (c), step (d) further including, at each station: (d1)stopping the expander; (d2) responsive to outward radial force from theexpander, increasing an interior diameter of the host pipe; and (d3)moving the expander to the next station; (e) inserting a concatenatedstring of liner pipe sections inside the host pipe, step (e) furtherincluding: (e1) providing a plurality of cartridges, each cartridgeincluding (1) a liner pipe section, (2) at least one rod and (3) atleast one centering ball, wherein each rod and centering ball isreceived inside the liner pipe section such that each rod is stabilizedwithin the liner pipe section via frictional contact between eachcentering ball and the liner pipe section; (e2) inserting a firstcartridge into the host pipe, wherein the first cartridge has a leadingend and a trailing end as inserted into the host pipe, and in which asteel head is connected to the leading end of the first cartridge suchthat the at least one rod in the first cartridge is connected to thesteel head and the liner pipe section on the first cartridge is alsoconnected to the steel head; (e3) concatenating the at least one rod inthe first cartridge to the at least one rod in the second cartridge;(e4) concatenating the liner pipe section on the first cartridge to theliner pipe section on the second cartridge; and (e5) inserting thesecond cartridge into the host pipe; and (f) withdrawing the rods andcentering balls from within the concatenated string of liner pipesections.

It is therefore a technical advantage of the disclosed technology toenhance the patented trenchless pipe refurbishment described in thePrior Application for deployments in a confined space at one end of thehost pipe, where inserting a full length liner pipe is impractical (ifnot impossible). In preferred embodiments, a liner pipe is inserted insections into an expanded host pipe, bringing advantages of the PriorApplication's disclosed embodiments to confined space deployments.Further, by inserting the liner pipe in sections from one end, theamount of work that must be done in a confined space is minimized. Thedisclosed confined space technology has particular application torefurbishment of pipes or culverts under roads in mountain passes, wherethere are often steep inclines on one side of the road and openwaterways nearby on the other side of the road. Nearly all of therefurbishment work can be done in a confined space off-road on theincline side, minimizing work required near the waterway, and avoidingthe need to close the road completely during refurbishment. It will beunderstood, however, that the scope of this disclosure is not limited tosuch applications with steep inclines on one side of a road and openwaterways nearby on the other side of the road. Other applications,without limitation, may be when insufficient access to the host pipe forrefurbishment is caused by the presence of private property nearby,where egress onto such private property is prohibited.

Another technical advantage of the disclosed technology is that its“open barrel” design allows for liner pipe sections to arrive at thepusher box in “cartridge” form, with rods and wireframe centering ballsalready pre-loaded inside, such that the rod/liner pipe sectionassemblies are ready for immediate insertion into the host pipe. Thisfeature further minimizes the amount of work that must be done in aconfined space.

A further technical advantage is that, when space in the deploymentallows, “cartridges” of rod/ball/liner pipe sections may be made upbeforehand using off-the-shelf commercial inventory lengths of linerpipe (typically in ranges from about 3 feet to 7 feet in length). Inthis way, the cost of the cartridges may be standardized and optimized.

Another technical advantage of the disclosed technology is that thepusher box provides multifunctional hydraulic components. Thismultifunctional feature allows the pusher box to stay in place andperform multiple tasks during the entire pipe refurbishment process.Keeping the pusher box in place throughout the entire operation againminimizes and optimizes the amount of work that must be done in aconfined space.

Another technical advantage of the disclosed technology is thatexpansion forces on the host pipe are controlled and perpendicular tothe host pipe wall. Issues with the host pipe folding up like anaccordion during expansion and/or liner pipe insertion are obviated.Embodiments of the disclosed technology are also non-destructive to thehost pipe and preserve wherever possible the integrity of the host pipe,so that the host pipe may continue to contribute to operationallongevity once the pipe refurbishment job is finished.

Embodiments of the disclosed technology further expand the outsidediameter of the host pipe by separating the host pipe either side of acontrolled longitudinal cut, leaving the host pipe larger in diameterthan before. Introducing the inner liner pipe may thus, in certainapplications, preserve the operational diameter of the pipe once therefurbishment job is finished. This retention of operational diametermay be highly advantageous in applications where pipe flow or capacityis important.

Another advantage of the disclosed technology is that in presentlypreferred embodiments, the host pipe is completely expanded before theinner liner pipe is introduced. In the prior art, and particularly inpipe bursting techniques that are destructive to the host pipe, theinner liner pipe is generally inserted to follow right behind thebursting tool as the tool moves along the host pipe. Causing the innerliner pipe to follow right behind the bursting tool avoids prematurecollapse of the surrounding soil into the tunnel void created by theburst host pipe. However, coordination of deployment of the inner linerpipe right behind the pipe bursting can make the logistics of the jobdifficult. Further, should there be an unintended collapse of thesurrounding soil before the inner liner pipe can provide support, theinner liner pipe can become stuck, putting success of the job injeopardy.

By contrast, preferred embodiments of the disclosed technology fullyexpand the host pipe, and substantially retain the host pipe'sstructural integrity, before the inner liner pipe is introduced. In someembodiments, the expanded host pipe may also be temporarily stabilizedvia the introduction of capsules. The capsules are removed as the linerpipe sections are inserted. Since, in preferred embodiments, the hostpipe is completely ready to receive the inner liner pipe, and is stillsupporting the surrounding soil, the inner liner pipe sections can bedeployed quickly and efficiently. The disclosed technology is thuspredictive of a much higher job success rate. Moreover, unlikerefurbishment methods of the prior art (such as pipe bursting),embodiments of the disclosed technology create an annular space in whichgrout can be deployed, further enhancing the strength, performance andlongevity of the finished refurbishment job.

The grout (or other material) injected into the annular space betweenthe host pipe and new liner pipe provides additional advantages overconventional trenchless methods, which typically omit this step. First,it secures the new liner pipe in position so it does not move or settle.Next, the grout fills voids in the soil under the host pipe, reducingthe likelihood of pipe deflections from differential settlement. Thegrout also fills voids in the soil above the host pipe, which reducespoint loads and impacts caused if those voids collapse (which is a majorsource of operational deflection and collapse of culverts). The groutalso distributes point loading on the host pipe/liner pipe construction,which may deter future cracking during service.

The foregoing has outlined rather broadly some of the features andtechnical advantages of the disclosed trenchless pipe refurbishmenttechnology, in order that the detailed description that follows may bebetter understood. Additional features and advantages of the disclosedtechnology may be described. It should be appreciated by those skilledin the art that the conception and the specific embodiments disclosedmay be readily utilized as a basis for modifying or designing otherstructures for carrying out the same inventive purposes of the disclosedtechnology, and that these equivalent constructions do not depart fromthe spirit and scope of the technology as described.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the embodiments described in thisdisclosure, and their advantages, reference is made to the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a view of an exemplary confined space environment in whichdeployment of the disclosed technology is applicable;

FIGS. 2A and 2B depict an excavation E including excavation pad 100 onwhich to deploy the pusher box 1150;

FIGS. 3A through 3G illustrate in more detail a currently preferredembodiment of pusher box 1150 as shown on FIGS. 2A and 2B, in which:FIGS. 3A and 3B are general exterior views; FIG. 3C depicts pusher box1150 in an extended state with exterior features removed; FIG. 3Ddepicts pusher box 1150 in a retracted state with one retract piston1192 omitted for clarity; FIGS. 3E and 3F depict pusher box 1150 in aretracted state with extend pistons 1191 and retract piston 1192 omittedfor clarity; and FIG. 3G is a view of pusher box 1150 in a partiallyextended state, illustrated with an exemplary liner pipe section 400;

FIGS. 4A and 4B illustrate embodiments of rod 410 in combination withwireframe centering balls 420, and FIG. 4C illustrates capsule 430;

FIGS. 5A and 5B illustrate two alternative embodiments of making alongitudinal cut LC in host pipe H;

FIGS. 6A and 6B depict one exemplary embodiment of an expander tool 300that may be used in embodiments of the disclosed technology; and FIGS.6C through 6F are “freeze frame” views depicting a first exemplaryembodiment of an expansion of host pipe H;

FIGS. 7A through 7F are a series of “freeze frame” illustrationsdepicting expansion of host pipe H;

FIGS. 8A and 8B are “freeze frame” views depicting a second exemplaryembodiment of an expansion of host pipe H;

FIG. 9 illustrates steel head 435 and cartridge 405 as deployed inembodiments for inserting concatenated liner pipe section 400 into hostpipe H;

FIGS. 10A through 10E are “freeze frame” views depicting a firstexemplary embodiment of insertion of concatenated liner pipe sections400 into an expanded host pipe H;

FIGS. 11A through 11E are “freeze frame” views depicting a secondexemplary embodiment of insertion of concatenated liner pipe sections400 into an expanded host pipe H;

FIG. 12 illustrates a section through liner pipe sections 400 residentinside host pipe H;

FIG. 13 illustrates grouting of annular space AS;

FIG. 14 illustrates inflatable bulkhead 500;

FIGS. 15 and 16 are sections as shown on FIG. 13; and

FIGS. 17 and 18 are detail views as shown on FIGS. 10B and 10Crespectively.

DETAILED DESCRIPTION

For the purposes of the following disclosure, FIGS. 1 through 18 shouldbe viewed together. Any part, item, or feature that is identified bypart number on one of FIGS. 1 through 18 has the same part number whenillustrated on another of FIGS. 1 through 18.

As noted above in the “Background” section, FIG. 1 illustrates anexemplary environment in which the disclosed technology is advantageousto refurbish the underground host pipe H. To recap, host pipe H on FIG.1 is buried beneath road R with steep incline SI on one side andwaterway W on the other side. In the environment illustrated on FIG. 1,access to host pipe H on the waterway W side is from above only. Accessto host pipe H on the other side is very limited by steep incline SI. Insome instances, host pipe H may be up to 80 feet long, making insertionof a new one-piece liner pipe into host pipe H impractical, if notimpossible.

FIGS. 2A and 2B illustrate an excavation E that may be needed on thesteep incline SI side of road R to facilitate some deployments of thedisclosed technology. It will be appreciated from FIG. 2A that access isneeded to the steep incline SI end of host pipe H, even though suchaccess is in a confined space. It will be further appreciated from FIG.2A that in exemplary mountain highway deployments such as illustrated onFIG. 1, existing roadside ditches on the steep incline SI side of road Rmay be of limited width B (for example, only 3 feet to 6 feet wide).FIG. 2A illustrates that in order to accommodate pusher box 1150 (asdescribed in more detail below), embodiments of which may be 9 feet to10 feet in length, steep incline SI may need to be excavated to extendedwidth A around host pipe H (for example, 10 feet to 12 feet). Further,FIG. 2A shows that in illustrated embodiments, sufficient depth ofexcavation E is required to set pusher box 1150 at a correct elevationto service host pipe H. Excavation E is made to provide such clearanceand depth. In some deployments (not illustrated) a retaining wall orother safety measure may be deployed to stabilize steep incline SI inthe presence of excavation E. Also, as shown on FIG. 2A, the bottom ofexcavation E advantageously provides a leveled and compacted excavationpad 100 on which to set, level and stabilize pusher box 1150. FIG. 2Bshows pusher box 1150 positioned in excavation E ready to service hostpipe H.

FIGS. 3A through 3G illustrate in more detail a currently preferredembodiment of pusher box 1150 as shown on FIGS. 2A and 2B. FIGS. 3A and3B are general exterior views. FIGS. 3C through 3F are various viewswith some parts omitted to enable the internals of pusher box 1150 to beseen more clearly. FIG. 3C depicts pusher box 1150 in an extended statewith exterior features removed. FIG. 3D depicts pusher box 1150 in aretracted state with one retract piston 1192 omitted for clarity. FIGS.3E and 3F depict pusher box 1150 in a retracted state with extendpistons 1191 and retract piston 1192 on the foreground side omitted forclarity. FIG. 3G is a view of pusher box 1150 in a partially extendedstate, illustrated with an exemplary liner pipe section 400 in order todescribe pusher box 1150's features with respect to handling liner pipesections 400.

As noted, FIGS. 3A and 3B are general exterior view of a currentlypreferred embodiment of pusher box 1150. Preferred embodiments of pusherbox 1150 weigh about 16,000 lbs, and are designed to deliver up to about85,000 lbs of horizontal force in order to insert a liner pipe insections into host pipe H. Given these metrics, it will be appreciatedthat careful positioning, leveling, alignment and stabilization ofpusher box 1150 to address host pipe H will assist smooth operation ofpusher box 1150. Referring also to FIGS. 2A and 2B, vertical stabilizers1155 on FIGS. 3A and 3B extend and retract (advantageously, underhydraulic power) to level pusher box 1150 on excavation pad 100 and toset pusher box 1150 to address host pipe H at the correct elevation andazimuth/angle. Front and back horizontal stabilizers 1156A and 1156B onFIG. 3B extend to stabilize pusher box 150 against the surroundingvertical excavation walls depicted in excavation E on FIGS. 2A and 2B.Front and back horizontal stabilizers 1156A and 1156B are againadvantageously hydraulically powered. In the illustrated embodiment ofFIG. 3B, front horizontal stabilizer 1156A is a U-shaped plate and ispositioned in excavation E on FIG. 2A such that host pipe H is locatedin the “U”. This feature on front horizontal stabilizer 1156A assistswith positioning pusher box 1150 to address host pipe H at the correctelevation and azimuth/angle.

FIGS. 3A and 3B also depict other exterior features of the illustratedembodiment of pusher box 1150. Control panel 1157 is positioned for anoperator/controller to stand on step 1158 and be sheltered by protectiveshoring 1159 from any loose debris that may fall from above.

FIGS. 3C through 3G should be viewed together to understand features ofthe illustrated embodiment of pusher box 1150. Looking at FIGS. 3C, 3D,3E and 3F together, pusher box 1150 includes pusher box frame 1174, andfront plates 1197 opposing back plates 1196. Front plates 1197 and backplates 1196 are ultimately connected to pusher box flame 1174. Pusherbox 1150 further provides rod connector 1160 on rod connector carriage1190. Rod connector 1160 is disposed to connect to a rod deployed insidea pipe section workpiece (such as rod 410 deployed inside liner pipesection 400 as described further below). Pusher box 1150 furtherprovides; extend and retract pistons 1191 and 1192 for extending andretracting rod connected carriage 1190, rod rotator 1162 for rotatingrod connector 1160, and elevator 1170 for supporting the workpiece at adesired elevation with respect to rod connector carriage 1190 while rodconnector carriage 1190 extends or retracts, and/or while rod connector1160 rotates.

Referring to FIGS. 3C and 3D, the illustrated embodiment of pusher box1150 provides rod connector 1160 with a hollow non-circular profile,which allows for greater torque when rotating a rod attached thereto (asfurther described below). Rod connector 1160 is attached to rodconnector carriage 1190 via rod rotator 1162. Rod rotator 1162 isdescribed in greater detail below with reference to FIGS. 3E and 3F. OnFIGS. 3C and 3D, however, it will be seen that rod connector carriage1190 moves within pusher box 1150 between an extended state on FIG. 3Cand a retracted state on FIG. 3D.

FIGS. 3C and 3D depict extend pistons 1191 positioned between pusher boxback plates 1196 and rod connector carriage 1190. It will be seen onFIGS. 3C and 3D that when extend pistons 1191 are extended, extendpistons 1191 push rod connector carriage 1190 away from back plates1196, causing rod connector carriage 1190 to travel away from backplates 1196. It will be further understood that retract pistons 1192retract while extend pistons 1191 extend. Pusher box 1190 thus movesinto an extended state as illustrated on FIG. 3C.

It will be further seen on FIGS. 3C and 3D that the converse occurs tomove pusher box 1150 into a retracted state. FIGS. 3C and 3D depictretract pistons 1192 positioned between pusher box front plates 1197 androd connector carriage 1190. When retract pistons 1192 are extended,retract pistons 1192 push rod connector carriage 1190 away from frontplates 1197, causing rod connector carriage 1190 to travel away fromfront plates 1197. It will be further understood that extend pistons1191 retract while retract pistons 1192 extend. Pusher box 1190 thusmoves into a retracted state as illustrated on FIG. 3D.

It will be appreciated that as deployed, embodiments of pusher box 1150will be more likely to face demand for a heavier “extend” load and alighter “retract” load. For this reason, the illustrated embodiment ofpusher box 1150 provides four (4) extend pistons 1191 and two (2)retract pistons 1192, although the scope of this disclosure is notlimited in either of these regards.

The embodiment of pusher box 1150 illustrated on FIG. 3C also showsfront plate reinforcement 1193 provided on front plates 1197. Similarly,as also shown on at least FIGS. 3C and 3G, back plate reinforcement 1194is provided on back plates 1196. Such front and back plate reinforcement1193, 1194 gives front and back plates 1197 and 1196 additional in orderto deter front and back plates 1197 and 1196 from bending in response toextension of retract and extend pistons 1192 and 1191 under operationalloads.

With reference to FIG. 3C and then FIG. 3B, it will be noted that fronthorizontal stabilizer plate 1156A on FIG. 3B has been omitted from FIG.3C to enable the internals of the illustrated embodiment of pusher box1150 to be viewed. FIG. 3C depicts front horizontal stabilizer pistons1146A, which will be understood to actuate horizontal motion of fronthorizontal stabilizer plate 1156A depicted on FIG. 3B.

FIGS. 3D, 3E and 3F further show elevator 1170 deployed under the travelof rod connector carriage 1190. As noted above, elevator 1170 isconfigured to support a workpiece (such as liner pipe section 400 asdescribed further below) at a desired elevation with respect to rodconnector carriage 1190 while rod connector carriage 1190 extends orretracts, and/or while rod connector 1160 rotates. In the illustratedembodiment of pusher box 1150 on FIGS. 3D, 3E and 3F, elevator 1170 ispreferably a cradle arrangement that may be hydraulically raised andlowered from underneath. As shown in detail on FIG. 3F, currentlypreferred embodiments of elevator 1170 include cradle 1171 disposed tobe raised and lowered by corresponding extension and retraction ofelevator piston 1172. Elevator 1170 further includes a plurality ofelevator guide bars 1173, wherein each elevator guide bar 1173 ispreferably rotatably pinned at a first end to cradle 1171 and at asecond end to pusher box frame 1174. When cradle 1170 raised and loweredby corresponding extension and retraction of elevator piston 1172,cradle 1171 is maintained substantially horizontal during said raisingand lowering via cooperating rotation of elevator guide bars 1174.

As noted above, FIGS. 3C and 3D show rod connector 1160 is attached torod connector carriage 1190 via rod rotator 1162. FIGS. 3E and 3Fillustrate two alternative embodiments of rod rotator 1162. On theembodiment of FIG. 3E, opposing rod rotator pistons 1195 cooperativelyextend and retract above/below rod connector 1160. In this way, opposing180-degree directions of rotation combine to provide 360-degree absolutepositioning for rod connector 1160. On the embodiment of FIG. 3F, rodrotator motor 1199 rotates rod connector 1160. Rod rotator motor 1199may be any suitable motor, such as hydraulic or electric, and the scopeof this disclosure is not limited in this regard.

FIG. 3G is a view of the illustrated embodiment of pusher box 1150 in apartially extended state. In FIG. 3G, pusher box 1150 is illustratedwith an exemplary liner pipe section 400. FIG. 3G depicts liner pipesection 400 supported from underneath on elevator 1170. In exemplarydeployments according to this disclosure, rod 410 and wireframecentering balls 420 would be provided inside liner pipe section 400 (seeFIGS. 4A and 4B and associated disclosure below), but are omitted forclarity on. FIG. 3G. Rod 410 would be connected to rod connector 1160 insuch exemplary deployments. It will thus be appreciated that travel ofrod connector carriage 1190 between an extended and a retracted state asshown on FIG. 3G will cause corresponding extension or retraction ofliner pipe section 400 (or corresponding extension/retraction of anyother workpiece to Which rod connector 1160 may be attached via rods410). Likewise, rotation of rod rotator 1162 will cause correspondingrotation of liner pipe section 400 (or corresponding rotation of anyother workpiece to which rod connector 1160 may be attached via rods410).

FIGS. 4A and 4B illustrate rod 410 in combination with wireframecentering balls 420. As also described elsewhere in this disclosure,rods 410 may be concatenated into a string thereof as rods 410 areinserted, preferably one at a time, into host pipe H by pusher box 1150.Conversely, rods 410 may be disconnected from a string thereof as rodsare retracted, preferably one at a time, out of host pipe H by pusherbox 1150. Rods 410 may be joined together end-to-end via any suitablehardware, such as bolts, pins or threaded connections, and thisdisclosure is not limited in this regard. Likewise, rods 410 may bejoined to rod connector 1160 on pusher box 1150 by any suitablehardware.

Wireframe centering balls 420 provide stability to concatenated stringsof rods 410, especially when such strings of rods 410 are undercompressive load while being “pushed” by pusher box 1150. It will beunderstood that there may be some applications where wireframe centeringballs 420 are not needed. However, preferred embodiments of thedisclosed technology deploy rods 410 in conjunction with wireframecentering balls 420. In embodiments of the disclosed technologydescribed below in which strings of rods 410 may be deployed to insertor retract tools into host pipe H (such as to make cuts in host pipe Hor expand host pipe H), wireframe centering balls 420 stabilize suchstrings of rods 410 directly against host pipe H. In embodimentsdescribed below in which strings of rods 410 are deployed to insertliner pipe sections 400 into host pipe H, preferred embodiments of thedisclosed technology provide cartridges 405 of rods 410 and wireframecentering balls 420 within liner pipe sections 400 as illustrated onFIG. 4B. Cartridges 405 are preferably made up offsite or away from theconfined space in which the disclosed technology is deployed. However,the scope of this disclosure of the present application is not limitedin this regard. Preferably, in each cartridge 405, the liner pipesection 400 is approximately the same length as one of the rods 410.Cartridge 405 may be assembled as follows: rod 410 is inserted intoliner pipe section 400, and is centered and frictionally stabilizedwithin liner pipe section 400 with wireframe centering balls 420 thatare attached to rod 410 along rod 410's length. Wireframe centeringballs 420 are sized and shaped to frictionally engage the internalsurface of liner pipe section 400 so that liner pipe section 400 may beinserted into host pipe H by rod 410. In preferred embodiments, rods 410are stabilized in each liner section 400 by two (2) wireframe centeringballs 420, although the scope of this disclosure is not limited in thisregard.

FIG. 4C illustrates capsule 430. In some embodiments described below,concatenated strings of capsules 430 may be temporarily inserted intohost pipe H in order to stabilize host pipe H. Capsules 430 will bedescribed below in more detail with reference to such embodiments inwhich they may be deployed.

It will be understood that the scope of this disclosure is not limitedto the wireframe construction of wireframe centering balls 420 andcapsules 430 illustrated on FIGS. 4A and 4B. While wireframeconstruction is presently preferred, any suitable construction(including solid construction and/or from materials other than metal) isconsidered within the scope of this disclosure. However, embodiments ofwireframe centering balls 420 and capsules 430 having wireframeconstruction provide an additional advantage of allowing water (or otherfluid) flow therethrough. This aspect can be advantageous in deploymentswhere groundwater, rainfall, snow melt or other fluid flow through hostpipe H or liner pipe sections 400 must be accounted for, and in which abuildup of such fluid behind solid embodiments of wireframe centeringballs 420 or capsules 430 would be disadvantageous.

Embodiments of methods for refurbishing an existing host pipe will nowbe described. Generally stated, a first phase in presently preferredembodiments is to make a longitudinal cut in the host pipe. A secondphase is an expansion phase, wherein the host pipe is expanded,preferably nondestructively, via separation of the longitudinal cut. Athird phase is to insert liner pipe sections into the expanded hostpipe. In the disclosed technology for deployments in confined spaces,sections of liner pipe are concatenated end-to-end as they are insertedinto the host pipe. In some embodiments, the expansion phase and theliner pipe section insertion phase may be combined. Once the liner pipesection insertion phase is complete, the host pipe and the liner pipe(in concatenated sections) typically form an annular space between them.A fourth phase of the presently preferred embodiments is to grout theannular space.

FIGS. 5 and 5B illustrate two alternative embodiments of making alongitudinal cut LC in host pipe H. FIG. 5A illustrates a longitudinalcut LC being made in host pipe H by cutting machine 200. In theembodiment depicted on FIG. 5A, cutting machine 200 is a self-propelledcutting tool running on a track as described in the Prior Application(incorporated herein by reference). Cable 201 on FIG. 5A may be used tosupply cutting machine 200 with power if cutting machine 200 isself-propelled. In other embodiments, cable 201 may also be used to pullcutting machine 200 along if cutting machine 200 is not self-propelled,or if cutting machine 200 is only partially self-propelled.

FIG. 5B illustrates an alternative embodiment in which cutting machine200 is connected to concatenated rods 410 inserted and retracted bypusher box 1150. On FIG. 5B, cutting machine 200 provides cuttingmachine rod connector 250, to which transitional rod 210 is attached.Transitional rod 210 is connected to a concatenated string of rods 410.Rods 410 preferably have wireframe centering balls 420 attached per thedisclosure above associated with FIG. 4A. It will be understood that theembodiments depicted on FIGS. 5A and 5B and in the Prior Application areexemplary, and that the scope of this disclosure is not limited as tospecific cutting tools or methods with which longitudinal cut LC is madein host pipe H. For example, alternative embodiments may makelongitudinal cut LC starting at the near end of host pipe H to pusherbox 1150 and traveling to the far end, such as are disclosed in U.S.Provisional Patent Application Ser. No. 62/471,389, incorporated hereinby reference.

Turning now to an expansion phase, FIGS. 6A and 6B depict one exemplaryembodiment of an expander tool (or “expander”) 300 that may be used inembodiments of the disclosed technology. FIG. 6A illustrates expander300 in a retracted state, with floating pad 301 in a “closed” position.Conversely, FIG. 6B illustrates expander 300 in an extended state, withfloating pad 301 shown in section in an “open” position. FIG. 6B depictsexpander 300 providing an expander rod connector 302 on each end. FIG.6B further depicts the internals of expander 300, in whichlongitudinally disposed expander pistons 303A/B actuate rams 304A/Blongitudinally away from each other. Rams 304A/B in turn displace firstwedges 305A/B longitudinally against second wedges 306A/B to createaxial displacement of thrust pads 307A/B. Thrust pads 307A/B areconnected to floating pad 301. It will thus be understood that floatingpad 301 may be extended or retracted on expander 300 by hydraulicallyextending or retracting expand pistons 303A/B.

It will be understood that the scope of this disclosure is not limitedto expander 300 as illustrated in FIGS. 6A and 6B. The embodiment ofexpander 300 on FIGS. 6A and 6B is comparatively light and has acomparatively small footprint, making it useful for deployments in smalldiameter host pipes. It is also highly reliable, having few movingparts. Other embodiments of an expander suitable for use in thedisclosed technology are described in the Prior Application(incorporated herein by reference). It will be understood that theembodiments depicted on FIGS. 6A and 6B and in the Prior Application areexemplary, and that the scope of this disclosure is not limited as tospecific expanders for expanding the host pipe.

FIGS. 6C through 6F are “freeze frame” views depicting a first exemplaryembodiment of an expansion of host pipe H. On FIG. 6C, expansion beginswith pusher box 1150 inserting expander 300 all the way to the far endof host pipe H via concatenation of inserted rods 410. It will beappreciated that in the embodiment illustrated on FIGS. 6C though 6F,expansion of host pipe H is accomplished starting at the far end of hostpipe H from pusher box 1150, and then pulling expander 300 throughsequential expansion stations towards pusher box 1150. However, thescope of this disclosure is not limited in this regard, and in otherembodiments, expansion may start at the near end of host pipe to pusherbox 1150, such as is disclosed in U.S. Provisional Patent ApplicationSer. No. 62/471,389, incorporated herein by reference.

Referring again to FIG. 6C, expander 300 provides expander rod connector302, to which transitional rod 310 is attached. Transitional rod 310 isconnected to a concatenated string of rods 410. Rods 410 preferably havewireframe centering balls 420 attached per the disclosure aboveassociated with FIG. 4A.

Referring now to FIG. 6D, floating pad 301 on expander 300 is extendedto expand host pipe H at a first expansion station at the far end ofhost pipe H from pusher box 1150. As will be described below in moredetail with reference to FIGS. 7A through 7F, expansion of host pipe Hpreferably comprises extension and retraction of floating pad 301 atselected rotational positions about expander 300's longitudinal axis.Rotation of expander 300 is accomplished using torque on rods 410connected to expander 300, where such torque is delivered onto rods 410by rod rotator 1162 on pusher box 1150 (refer to disclosure aboveassociated with FIGS. 3E and 3F, for example). FIG. 6D further showsthat in so e embodiments, the connection between transitional rod 310and rods 410 may need to pivot to accommodate extension of floating pad301 on expander 300.

FIG. 6E illustrates expansion of host pipe H completed at a firstexpansion station at the far end of host pipe H from pusher box 1150,and expander 300 moved to a second expansion station by retraction ofrods 410 by pusher box 1150. At this point, an expansion of host pipe Hat the second expansion station will be undertaken. It will beunderstood that once expansion at the second expansion station iscomplete, expander 300 will be moved to a third expansion station byretraction of rods 410, and so on, until expansion of host pipe H iscomplete. FIG. 6D shows expansion of host pipe H as being complete, withexpander 300 awaiting removal while supported by elevator 1170 on pusherbox 1150.

FIGS. 7A through 7F are a series of “freeze frame” illustrationsdepicting expansion of host pipe H at an expansion station, such asillustrated, for example, on FIG. 6D. FIGS. 7A though 7F will beunderstood to be end elevation views looking into the far end of hostpipe H from pusher box 1150 on FIG. 6D, for example, during expansion.

FIG. 7A depicts expander 300 sitting in host pipe H immediately beforeexpansion begins. Longitudinal cut LC in host pipe H is shown in anunseparated state.

In FIG. 7B, floating pad 301 on expander 300 extends to commenceexpansion of host pipe H. In FIG. 7C, expander 300 and floating pad 301engage host pipe H to expand in the direction of the arrows on FIGS. 7Band 7C. Host pipe H deforms in response, causing initial separation oflongitudinal cut LC. In preferred embodiments, expansion of host pipe His done nondestructively to host pipe H. Likewise, separation oflongitudinal cut LC is preferably non-elastic (i.e. plastic) separation.

Floating pad 301 is retracted between FIGS. 7C and 7D, and then expander300 is partially rotated to a new rotational position about expander300's longitudinal axis. It will be understood from disclosure abovethat such rotation of expander 300 is responsive to torque delivered byrotator rod rotator 1162 on pusher box 1150 and applied via rods 410connected to expander rod connector 302. FIG. 7D depicts expansion ofhost pipe Hat a second rotational position. Longitudinal cut LCcontinues separate. Floating pad 301 is retracted again between FIGS. 7Dand 7E, and expander 300 is rotated to a third rotational position. FIG.7E depicts expansion of host pipe H at the third rotational position.Retraction, rotation and expansion continues wherein FIG. 7F depictsexpansion of host pipe H at a fourth rotational position, by which timehost pipe H is substantially uniformly expanded and longitudinal cut LCis separated.

While the embodiments of FIGS. 7A through 7F disclose four rotationalpositions from which to expand host pipe H, the scope of this disclosureis not limited in this regard. It will be understood that users willcustomize expansion procedures to the needs of the application, takinginto account variables such as, for example, amount of host pipeexpansion and longitudinal cut separation desired at each expansionstation, or number of rotational positions from which to expand.

FIGS. 8A and 8B are “freeze frame” views depicting a second exemplaryembodiment of an expansion of host pipe H. The embodiment illustrated onFIGS. 8A and 8B is similar to the embodiment illustrated on FIGS. 6Cthrough 6F, except that capsules 430 are concatenated to follow expander300 into expanded sections of host pipe H. Capsules 430 are illustratedand described above with reference to FIG. 4C. It will be understoodfrom FIG. 8A that capsules 430 are attached to expander rod connector302 via entry into the far end of host pipe H from pusher box 1150.Capsules 430 are concatenated into a string thereof attached to expanderrod connector 302 as expander 300 moves towards pusher box 1150(responsive to pusher box retracting rods 410). Once expander 300 hascompleted expansion of host pipe 300 at a first expansion station, afirst capsule 430 is attached to expander 300 via connection withexpander rod connector 302. As expander 300 moves towards pusher box1150 and a second expansion station, additional capsules 430 areconcatenated into a string thereof via continued entry into the far endof host pipe H. Capsules 430 may be joined together end-to-end via anysuitable hardware, such as bolts, pins or threaded connections, and thisdisclosure is not limited in this regard. Likewise, capsules 430 may bejoined to expander rod connector 302 by any suitable hardware.

FIG. 8B illustrates completion of expansion of host pipe H with aconcatenated string of capsules 430 temporarily resident in the expandedhost pipe H. It will be understood that the embodiment of FIGS. 8A and8B is advantageous in deployments where the expanded host pipe H isunstable, or when collapse of expanded host pipe H is a concern. Theembodiment of FIGS. 8A and 8B is advantageous when, for example, hostpipe H is highly corroded and/or brittle, or the earthwork surroundinghost pipe H is unstable. In such environments, capsules 430 provideadditional temporary support to expanded host pipe H until a liner pipecan be introduced.

The embodiment of FIGS. 8A and 8B is further advantageous in deploymentswhere expansion efforts are proving difficult to achieve non-elasticexpansion and separation. That is, in deployments where host pipe Htends to return elastically to its unexpanded condition despiteexpansion efforts. Insertion of a liner pipe in such deployments mightprove difficult where the liner pipe has a comparable diameter to theoriginal, unexpanded host pipe. The introduction of capsules 430 in suchdeployments, such as in the embodiment illustrated on FIGS. 8A and 8B,temporarily assists maintaining expanded host pipe H at its expandeddiameter until a liner pipe can be introduced.

Although not illustrated in this disclosure, deployment of capsules 430during the cutting phase may also be useful in some embodiments wherethe host pipe is particularly unstable after a longitudinal cut is made(per FIGS. 5A and 5B above with associated description). With momentaryreference to FIGS. 5B and 8A/8B together, a string of capsules 430 maybe deployed in host pipe H behind cutting machine 200 during the cuttingphase in the manner described on FIGS. 8A/8B with reference to expander300.

FIG. 9 illustrates the interoperation of steel head 435 and cartridge405 as deployed in embodiments of the disclosed technology for insertingconcatenated liner pipe section 400 into an expanded host pipe H. Itwill be recalled from disclosure above associated with FIG. 4B thatcartridge 405 comprises rod 410 inserted into liner pipe section 400,wherein rod 410 is centered and frictionally stabilized within linerpipe section 400 with wireframe centering balls 420. Wireframe centeringballs 420 are attached to rod 410 along rod 410's length. Wireframecentering balls 420 are sized and shaped to frictionally engage theinternal surface of liner pipe section 400 so that liner pipe section400 may be inserted into host pipe H by rod 410. FIG. 9 illustrates aninitial cartridge 405 for insertion into host pipe H, to which steelhead 435 is attached at the leading end. In greater detail, steel head435 is attached to rod(s) 410 inside initial liner pipe section 400, sothat when pusher box 1150 (not illustrated on FIG. 9) inserts initialcartridge 405 into host pipe H by connection to rods 410, steel head 430will be driven into host pipe H by rods 410.

Liner section 400 on FIG. 9 is also preferably connected to theperiphery of steel head 430. In this way, as rods 410 drive steel head435 into host pipe H, liner pipe sections 400 will then be dragged alongby steel head 435. With further reference to the embodiment illustratedon FIG. 8, steel head 435 advantageously has a dead weight and isconically shaped. Steel head 435 thus promotes smooth insertion of anentire concatenated string of rods 410/liner pipe sections 400 into thehost pipe H. In particular, steel head 435 protects the leading edge ofthe first liner pipe section 400 from snagging against corrugations andminor peripheral obstructions in the interior of host pipe H.

Although not specifically illustrated, one embodiment of steel head 435advantageously provides an internal vibrator. Another embodiment ofsteel head 435 (also not illustrated) provides an internal jar or impacthammer, preferably driven hydraulically or pneumatically. The vibratoror impact hammer vibrates or jolts steel head 435 (and at least theleading rods 410/liner pipe sections 400 attached to steel head 435)against the host pipe H interior as they are inserted into the host pipeH, thereby encouraging movement of the string in the face of frictionaldrag against the interior of host pipe H. In other embodiments (also notillustrated), the vibrator or impact hammer could be provided in pusherbox 1150.

FIGS. 10A through 10E are “freeze frame” views depicting a firstexemplary embodiment of insertion of concatenated liner pipe sections400 into an expanded host pipe H. When insertion is complete, aconcatenated string of liner pipe sections 400 is left resident in hostpipe H and forms a continuous liner pipe. Liner pipe sections 400 may bemade of any suitable liner pipe material, such as, without limitation,galvanized metal, aluminized steel, asphalt coated steel plastic,ceramic or a fiber reinforced resin compound. Similarly, liner pipesections 400 may be corrugated or smooth. Liner pipe sections 400 forany given deployment may also be uniform in construction or hybrid. Thescope of this disclosure is not limited in any of these regards.

Referring first to FIG. 10A, pusher box 1150 is inserting an initialliner pipe section 400 into host pipe H. Throughout FIGS. 10A through10E, it will be understood that liner pipes 400 are preferably insertedin the form of cartridges 405 as illustrated and described above withreference to FIG. 4B, in which liner pipe sections 400 are deployed withrods 410 and wireframe centering balls 420 assembled inside. It will bealso seen and understood on FIG. 10A that initial liner pipe section 400(and rods 410 inside liner pipe section 400, hidden from view) areconnected to steel head 435 in the manner described above is inassociation with FIG. 9.

With continuing reference to FIG. 10A, rod connector 1160 on pusher box1150 will be understood to be connected to rods 410 inside liner pipesection 400. Pusher box 1150 inserts steel head 435 and initial linerpipe section 400 into host pipe H as pusher box 1150 is actuated towardsits extended state. Elevator 1170 on pusher box 1150 is set to asuitable height to facilitate entry of steel head 435 and initial linerpipe section 400 into host pipe H.

FIG. 10B depicts where a second liner pipe section 400 has beenconcatenated to the initial liner pipe section 400. Pusher box 1150 isshown in its fully retracted state It will be understood that betweenFIGS. 10A and 10B, pusher box 1150 was actuated to its fully extendedstate, whereupon rod connector 1160 was disconnected from rods 410inside the initial leer pipe section 400. Pusher box 1150 was thenretracted to its fully retracted state. A second cartridge 405 was thendeployed on elevator 1170. The rods 410 in the second cartridge 405 werethen connected to the rod connector 1160 at one end, and to the rods 410inside the initial liner pipe section 400 at the other end (rodconnections hidden from view on FIG. 10B).

FIG. 10B also illustrates the two illustrated liner pipe sections 400joined together. FIG. 17 illustrates one embodiment of such joint ingreater detail. In the exemplary embodiment illustrated on FIG. 17,initial and second liner pipe sections 400 are connected with aconnector clamp 450 secured by bolts 455. In other embodiments, notillustrated, initial and second liner pipe sections 400 mayalternatively be connected via rivets in drilled holes, or via adhesive,or via tack welds once a connection is made using temporary flanges. Thescope of this disclosure is not limited in this regard.

FIG. 10C and FIG. 18 illustrate a further exemplary embodiment ofjoining two liner pipe sections 400 together, in which liner pipesections 400 are threaded together via threaded connection 460. FIG. 10Cillustrates rods 410 and wireframe centering halls 420 inside liner pipesections 400. In the embodiment illustrated on FIG. 10C, rods 410 insidesecond liner pipe section 400 are initially only connected to rodconnector 1160 on pusher box 1150. Torque T is then delivered to secondliner pipe section 400 via rotation of rods 410 inside second liner pipesection by rod rotator 1162 on pusher box 1150. Rotation of rods 410causes corresponding rotation of second liner pipe 400 via frictionalcontact of wireframe centering balls 420 against the inside surface ofsecond liner pipe section 400. (Note that rod rotator 1162 is notillustrated on pusher box 1150 on FIG. 10C. Refer to FIGS. 3E and 3Fabove, with associated disclosure, for a discussion of the operation ofembodiments of rod rotator 1162). Torque T as shown on FIG. 10C causesrotation of second liner pipe section 400 at threaded connection 460 (onFIG. 18), which in turn enables initial and second liner pipe sections400 to be threaded together. In some embodiments, the threading togetherof initial and second liner pipe sections 400 will take about 2-6revolutions of second liner pipe section 400 at threaded connection 460,although the scope if this disclosure is not limited in this regard.Once threaded connection 460 is made, rods 410 on initial liner pipesection 400 may then be connected to rods 410 on second liner pipesection.

Referring now to the exemplary embodiments illustrated on both FIGS. 10Band 10C, pusher box 1150 may be actuated towards its extended state onceinitial and second liner pipe sections 400 are joined together and rods410 are connected throughout. Actuation towards pusher box 1150'sextended state will cause insertion of initial and second liner pipesections 400 (as attached to steel head 435) further into host pipe H.

Comparing FIGS. 10B and 10C to FIG. 10D, pusher box 1150 has moved toits fully extended state, rods 410 in second liner pipe section 400 havebeen disconnected from rod connector 1160 on pusher box 1150, pusher box1150 has been retracted to its fully retracted state, and a thirdcartridge 405 has been deployed on elevator 1170. The sequence ofoperations described above with reference to FIG. 10B is now repeatedwith respect to FIG. 10D, in which rods 410 and liner pipe sections 400are connected/joined, liner pipe sections 400 are inserted further intohost pipe H via actuation of pusher box 1150 towards its fully extendedstate, rods 410 are disconnected from rod connector 1160, pusher box1150 is retracted to its fully retracted state, and another cartridge405 is introduced to pusher box 1150.

FIG. 10E illustrates completion of liner insertion operations, in whicha concatenated string of liner pipe sections 400 are joined together toform a continuous liner pipe inside host pipe H. FIG. 10E shows steelhead 435 being disconnected and removed from a far end of host pipe H.Although not specifically illustrated, it will be understood that rods410 inside liner pipe sections 400 are now retracted with wireframecentering balls 420 attached. Retraction of rods 410 is essentially thereverse operation to the insertion operation described immediately abovewith reference to FIGS. 10B and 10D. Rod connector 1160 on pusher box1150 is connected to rods 410 in a fully extended state. Pusher box 1150is then retracted to its fully retracted state, which causes rods 410 tobe withdrawn/retracted out of liner pipe section 400 while leaving linerpipe sections 400 resident inside host pipe H. In preferred embodiments,the dead weight of the fully concatenated string of liner pipe sections400, plus its frictional resistance from contact with host pipe H alongits entire length, will be sufficient to enable pusher box 1150 towithdraw rods 410 (with wireframe centering balls 420 attached) fromliner pipe sections 400 while leaving liner pipe sections 400 residentin host pipe H. Alternatively, steel head 435 may be left attached toliner pipe sections 400 while rods 410 are withdrawn. Once pusher box1150 reaches a fully retracted state, a first section of rods 410 (withwireframe centering balls 420 attached) may be disconnected from rodconnector 1160 on pusher box 1150 at one end, and from the concatenatedstring of rods 410 still inside the liner pipe at the other end. Pusherbox 1150 is then actuated to its fully extended state. Rod connector1160 is then connected to a second section of rods 410 ready for asecond retraction of rods 410. The process is continued until the entirestring of rods 410 (with wireframe centering balls 420 attached) isretracted section by section and removed.

FIGS. 11A through 11E are “freeze frame” views depicting a secondexemplary embodiment of insertion of concatenated liner pipe sections400 into an expanded host pipe H. Generally speaking, the embodiment ofFIGS. 11A through 11E is similar to the embodiment of FIG. 9 and FIGS.10A, 10B, 10D and 10E. However, the embodiment of FIGS. 11A through 11Edepicts insertion of liner pipe sections 400 in deployments whencapsules 430 have been left temporarily resident in host pipe H (per thedisclosure above associated with FIGS. 8A and 8B).

FIG. 11A is similar to FIG. 9. Capsule 405 (including rods 410 andwireframe centering balls 420 assembled inside liner pipe section 400)is shown on FIG. 11A connected to steel head 435 in the manner describedabove with reference to FIG. 9. Steel head 435 on FIG. 11A mayoptionally provide a vibrator or impact hammer (not illustrated) as alsodescribed above with reference to FIG. 9. FIG. 11A shows capsules 435previously deployed in host pipe H per FIGS. 8A and 8B above andassociated description.

FIGS. 11B through 11E are similar to FIGS. 10A, 10B, 10C and 10D. Linerpipe section 400 on FIGS. 11B through 11E is being inserted into hostpipe H in the manner described above with FIGS. 10A, 10B, 10C and 10D.It will be appreciated on FIGS. 11B through 11D, however, that steelhead 435 shunts capsules 435 out of the far end of host pipe H as linerpipe sections 400 are inserted into host pipe H. It will be understoodin the embodiment illustrated on FIGS. 11A through 11E that, althoughnot specifically illustrated, retraction of rods 410 (with wireframecentering balls 420 attached) from liner pipe sections 400 is per thedescription above associated with FIG. 10E.

FIGS. 10E and 11E depict an annular space AS formed between liner pipesections 400 and the host pipe H once the fully concatenated liner pipeis inserted and resident inside host pipe H. FIG. 12 illustrates asection through liner pipe sections 400 resident inside host pipe H perFIGS. 10E and 11E. FIG. 12 shows annular space AS and longitudinal cutLC (with longitudinal cut LC separated per the description aboveassociated with FIGS. 7A through 7F).

FIGS. 13 and 15 illustrate grouting of the annular space AS. Groutingmay be accomplished by any suitable protocol. FIGS. 13 and 15 illustrateone example of a suitable grouting protocol using specially developedinflatable bulkheads 500, illustrated on FIGS. 14 and 16, customized todispense liquid grout into annular space AS, and then retain the groutwhile it cures. This disclosure is not limited, however, to the groutprotocol illustrated and described with reference to FIGS. 13 and 15, ordeploying the inflatable bulkheads illustrated and described withreference to FIGS. 14 and 16.

FIG. 14 depicts inflatable bulkhead 500 comprising inflatable ring 530inflated via inflation valve 510. Inflatable ring 530 may be made fromconventional inflatable materials, such as rubber or rubber composites,and inflation valve 510 is conventional. Inflatable bulkhead 500 alsoincludes at least one (on FIG. 14, three) grout fittings 520. Groutfittings 520 pass through inflatable ring 530 and are conventionallysealed at their points of insertion through the wall of inflatable ring530. Grout fittings 520 are adapted to allow liquid grout to passthrough. They may be made of any conventional material such as brass,stainless steel, etc. Each grout fitting 520 has a connector on one endsuitable for connection with a conventional liquid grout hose.

FIG. 13 depicts grout G being injected into annular space AS.Preferably, annular space AS is completely filled with grout G. However,in some embodiments annular space AS may be at least partially filledwith grout G. Inflatable bulkheads 500 are installed into annular spaceAS at either end of host pipe H, and thereby seal annular space AS ateither end. Since inflatable bulkheads 500 are advantageously made ofrubber (or a rubber-like material) and are inflatable, the same bulkheadmay be used for several combinations of outside diameters of liner pipe400 and corresponding expanded internal diameters of host pipe H. Forthe same reason, inflatable bulkheads 500 provide good seals of annularspace AS at either end of host pipe H regardless of surface or shapeirregularities at points of contact with inflatable bulkheads 500.Consistent with the disclosure immediately above with reference to FIG.14, liquid grout G is injected into annular space AS on FIG. 13 throughone inflatable bulkhead 500 via grout fittings 520. Inflatable bulkheads500 retain grout G in annular space AS while grout G cures. Once grout Gis cured, inflatable bulkheads 500 may be deflated and removed. At thispoint, the assembly of host pipe H, concatenated liner pipe sections 400and grout G in annular space AS has a cross-section as shown on FIG. 15.

It will be appreciated from FIG. 13 that liquid grout G may be injectedinto annular space AS from either or both ends. If only injected fromone end, the inflatable bulkhead 500 at the non-injection end may be aplain bulkhead without grout fittings 520, or else the grout fittings520 at the non-injection end may be temporarily plugged.

FIG. 16 is a cross-section as shown on FIG. 13, and shows theoperational interface between inflatable bulkhead 500 and liner pipesection 400/host pipe H in more detail. Inflatable ring 530 is installedbetween liner pipe section 400 and host pipe H and inflated viainflation valve 510. Grout fitting(s) 520 dispense grout into annularspace AS between liner pipe section 400 and host pipe H.

Although not specifically illustrated on FIGS. 13 through 16, it may beadvantageous to stabilize concatenated liner pipe sections 400 duringgrouting operations. In some embodiments, such stabilization may viastabilization measures such as filling concatenated liner pipe sections400 with water or pressurizing with air while the grout cures, in orderto prevent possible deformation or even collapse of the liner pipe underthe weight or pressure of the liquid grout. Once cured, the grout detersdifferential settlement of the host pipe/liner pipe as a unitary groutedstructure. Further, with reference to FIG. 13, when fully pressurized,inflatable bulkheads 500 at either end provide strong temporarybulkheads that enable grout G to be delivered throughout annular spaceAS at pressure. As a result, grout G can fill all voids in annular spaceAS, including eroded voids that may be present in the soil barrier. Itwill be further understood that the term “grout” as used in thisdisclosure is not intended to be limited to cement-based grout. Thescope of this disclosure includes any suitable injectable grout, alsoincluding, without limitation, epoxy-based grouts.

Preferred embodiments described in this disclosure have referredthroughout to an embodiment of pusher box 1150 as described in detail onFIGS. 3A through 3G. It will be understood that the scope of thisdisclosure is not limited to such a pusher box embodiment. Alternativepusher box embodiments are within the scope of this disclosure, forexample as described in U.S. Provisional Patent Application Ser. No.62/471,389 incorporated herein by reference.

The scope of this disclosure also includes embodiments in which a hostpipe expansion phase is combined with a liner pipe section insertionphase. In such embodiments, a longitudinal cut is made in the host pipeper the above disclosure. An oversized liner pipe is then inserted intothe host pipe by the pusher box, in sections, with a similarly oversizedconically-shaped steel head attached to a leading end of the liner pipesections per the above disclosure. The oversized steel head expands thehost pipe via separation of the longitudinal cut as it is inserted intothe host pipe, and the liner pipe sections form a concatenated stringthereof immediately resident in the freshly-expanded host pipe. In suchembodiments, an annular space may or may not form between the host pipeand the concatenated host pipe sections. Grouting may be performed if asuitable annular space forms.

Although the inventive material in this disclosure has been described indetail along with some of its technical advantages, it will beunderstood that various changes, substitutions and alternations may bemade to the described embodiments without departing from the broaderspirit and scope of such inventive material as set forth in the appendedclaims.

I claim:
 1. A pusher box, comprising: at least one front plate opposingat least one back plate; a rod connector carriage wherein the rodconnector carriage is disposed to travel between the at least one frontplate and the at least one back plate, the rod connector carriageincluding a rod connector, the rod connector positioned on the rodconnector carriage facing the at least one front plate; the rodconnector carriage further including a rod rotator, wherein the rodrotator is disposed to selectively rotate the rod connector; at leastone extend piston interposed between the rod connector carriage and theat least one back plate, wherein extension of the at least one extendpiston causes the rod connector carriage to travel towards the at leastone front plate; at least one retract piston interposed between the rodconnector carriage and the at least one front plate, wherein extensionof the at least one extend piston causes the rod connector carriage totravel away from the at least one front plate; an elevator positionedunder the rod connector carriage, wherein the elevator is disposed sothat, when a workpiece is placed on the elevator, the elevator supportsthe workpiece at a desired elevation with respect to the rod connectorcarriage; and at least one front horizontal stabilizer and at least oneback horizontal stabilizer, the at least one front horizontal stabilizerand the at least one back horizontal stabilizer disposed so that, whenthe pusher box is received in an excavation, actuation of the at leastone front horizontal stabilizer against the excavation and actuation ofthe at least one back horizontal stabilizer against the excavationstabilizes the pusher box horizontally within the excavation.
 2. Thepusher box of claim 1, further comprising a pusher box frame, whereinthe at least one front plate and the at least one back plate areultimately attached to the pusher box frame, and in which the elevatorincludes: a cradle; an elevator piston; and a plurality of elevatorguide bars, wherein each elevator guide bar is rotatable connected at afirst end to the cradle and at a second end to the pusher box frame;wherein the cradle is disposed to be raised and lowered by correspondingextension and retraction of the elevator piston such that the cradle ismaintained substantially horizontal during said raising and lowering viacooperating rotation of the elevator guide bars.
 3. The pusher box ofclaim 1, in which the at least one, extend piston includes four extendpistons.
 4. The pusher box of claim 1, in which the at least one retractpiston includes two retract pistons.
 5. The pusher box of claim 1, inwhich selected ones of the at least one front plate include front platereinforcement.
 6. The pusher box of claim 1, in which selected ones ofthe at least one back plate include back plate reinforcement.
 7. Thepusher box of claim 1, further comprising a front horizontal stabilizerpiston, and in which the front horizontal stabilizer piston actuates theat least one front horizontal stabilizer against the excavation.
 8. Apusher box, comprising: at least one front plate opposing at least oneback plate; a rod connector carriage wherein the rod connector carriageis disposed to travel between the at least one front plate and the atleast one back plate, the rod connector carriage including a rodconnector, the rod connector positioned on the rod connector carriagefacing the at least one front plate; the rod connector carriage furtherincluding a rod rotator, wherein the rod rotator is disposed toselectively rotate the rod connector; at least one extend pistoninterposed between the rod connector carriage and the at least one backplate, wherein extension of the at least one extend piston causes therod connector carriage to travel towards the at least one front plate;at least one retract piston interposed between the rod connectorcarriage and the at least one front plate, wherein extension of the atleast one extend piston causes the rod connector carriage to travel awayfrom the at least one front plate; an elevator positioned under the rodconnector carriage, wherein the elevator is disposed so that, when aworkpiece is placed on the elevator, the elevator supports the workpieceat a desired elevation with respect to the rod connector carriage; atleast one front horizontal stabilizer, at least one back horizontalstabilizer, and at least one vertical stabilizer; the at least one fronthorizontal stabilizer and the at least one back horizontal stabilizerdisposed so that, when the pusher box is received in an excavation,actuation of the at least one front horizontal stabilizer against theexcavation and actuation of the at least one back horizontal stabilizeragainst the excavation stabilizes the pusher box horizontally within theexcavation; and the at least one vertical stabilizer disposed so that,when the pusher box is received in the excavation, actuation of the atleast one vertical stabilizer against the excavation levels the pusherbox within the excavation.
 9. A pusher box, comprising: a pusher boxframe; at least one front plate opposing at least one back plate,wherein the at least one front plate and the at least one back plate areultimately attached to the pusher box frame; a rod connector carriagewherein the rod connector carriage is disposed to navel between the atleast one front plate and the at least one back plate, the rod connectorcarriage including a rod connector, the rod connector positioned on therod connector carriage facing the at least one front plate, wherein therod connector is disposed to connect to a rod deployed inside a pipesection workpiece; at least one extend piston interposed between the rodconnector carriage and the at least one back plate, wherein extension ofthe at least one extend piston causes the rod connector carriage totravel towards the at least one front plate; at least one retract pistoninterposed between the rod connector carriage and the at least one frontplate, wherein extension of the at least one extend piston causes therod connector carriage to travel away from the at least one front plate;and an elevator positioned under the rod connector carriage, wherein theelevator is disposed so that, when the workpiece is placed on theelevator, the elevator supports the workpiece at a desired elevationwith respect to the rod connector carriage.
 10. The pusher box of claim9, in which the elevator includes: a cradle; an elevator piston; and aplurality of elevator guide bars, wherein each elevator guide bar isrotatably connected at a first end to the cradle and at a second end tothe pusher box frame; wherein the cradle is disposed to be raised andlowered by corresponding extension and retraction of the elevator pistonsuch that the cradle is maintained substantially horizontal during saidraising and lowering via cooperating rotation of the elevator guidebars.
 11. The pusher box of claim 9, in which the at least one extendpiston includes four extend pistons.
 12. The pusher box of claim 9, inwhich the at least one retract piston includes two retract pistons. 13.The pusher box of claim 9, in which the rod connector carriage furtherincludes a rod rotator, the rod rotator disposed to selectively rotatethe rod connector.
 14. The pusher box of claim 13, in which rotation ofthe rod rotator is enabled by a rod rotator motor.
 15. The pusher box ofclaim 13, in which rotation of the rod rotator is enabled by at leastone rod rotator piston.
 16. The pusher box of claim 9, in which selectedones of the at least one front plate include front plate reinforcement.17. The pusher box of claim 9, in which selected ones of the at leastone back plate include back plate reinforcement.
 18. The pusher box ofclaim 9, further comprising at least one front horizontal stabilizer andat least one back horizontal stabilizer, the at least one fronthorizontal stabilizer and the at least one back horizontal stabilizerdisposed so that, when the pusher box is received in an excavation,actuation of the at least one front horizontal stabilizer against theexcavation and actuation of the at least one back horizontal stabilizeragainst the excavation stabilizes the pusher box horizontally within theexcavation.
 19. The pusher box of claim 18, further comprising a fronthorizontal stabilizer piston, and in which the front horizontalstabilizer piston actuates the at least one front horizontal stabilizeragainst the excavation.
 20. The pusher box of claim 9, furthercomprising at one vertical stabilizer, the at least one verticalstabilizer disposed so that, when the pusher box is received in anexcavation, actuation of the at least one vertical stabilizer againstthe excavation levels the pusher box within the excavation.